Re: [patch 00/26] x64, x2apic/intr-remap: Interrupt-remapping and x2apic support

[Yinghai Lu]

On Sat, Jul 12, 2008 at 1:11 AM, Eric W. Biederman
<ebiederm@xxxxxxxxxxxx> wrote:
> "Yinghai Lu" <yhlu.kernel@xxxxxxxxx> writes:
>
>>>> also read the x2APIC spec pdf, it doesn't say anything about interrupt
>>>> remapping...need to be used with x2apic...
>>>
>>> Clustered logical mode won't work as it requires > 16 bits of apicid.
>>> So only flat physical mode will work.
>>
>> current read_apic_id in genx2apic_cluster and genx2apic_phys is the same...
>
> There is a fixed defined mapping between logical & physical mappings,
> so that may not be an issue.
>
> A logical cluster apicid is encoded with the high 16bits being the
> cluster number, and the low 16bits being a bitmap of which core
> in the cluster to send the irq to.  It sounded like a single
> cluster can not span multiple sockets.
>
> So in practice if you have 2 sockets you have a cluster id of 1.
> Which means physical apic ids over 16 and logical apicids over 65536.
is it like
0x0001, 0x0002, 0x0004, 0x0008, ...., 0x8000 in one cluster? so every
cluster only have 16

YH
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